You cured your first problem properly. An extended slide stop is prone to engaging if you shoot with a high thumb hold. Notice that most all carry pistols nowadays have the standard slide stop?

Your second problem is probably ammo related. Since the .45 ACP headspaces on the case mouth, the ammo you were using might have been overcrimped causing a taper at the mouth instead of a flat surface to headspace against. I created this problem for myself when I first started reloading.

As far as the shok-buff, I agree with the guy that told you to get rid of it.